DESCRIPTION: The investigator proposes the following specific aims: Aim #1: Study the physical interactions between adenylate cyclase (git2) and proteins directly involved in its activation. The PI has identified 8 altered git2 proteins that have normal in vitro catalytic activity (measured in the presence of Mn++) but are not functional in vivo (termed class 1). The mutations in 4 of the altered class 1 git proteins that were sequenced have mutations occurring within a small region of the gene (encoding about 8% of the protein). These mutations may identify a region of git2 that interacts with regulatory proteins. The PI has isolated extragenic suppressors (sgt) of 2 different class 1 git2 mutants. The PI proposed experiments and analysis are reasonable and should identify components involved in adenylate cyclase activation. Whether these suppressors identify components of the G protein pathway to activate git2 remains to be determined. In addition, the PI will use the 2-hybrid screen to identify git2-interacting proteins. The PI has a good secondary screen where he will concentrate on proteins that interact with wt git2 but not a class 1 altered git2.